The present invention relates to chewing gums, and in particular to gums containing flavorants of natural or artificial origin. The invention relates more particularly to gums having a particular flavoring component which comprises a specially prepared combination of flavorant and polymeric matrix.
The pertinent literature describes gum formulations in which the flavorant is entrapped, encapsulated, impregnated within porous microbeads or is otherwise physically surrounded.
One example is U.S. Pat. No. 4,711,784, which discloses chewing gum compositions including a high molecular weight polyvinyl acetate blended with a hydrophobic plasticizer which forms a film with the high molecular weight polyvinyl acetate. This film-coated polymer serves as an encapsulating composition for sweetener components such as aspartame. The film coating is considered necessary to control release of the sweetener during mastication of the gum, and to prevent undesired interaction between the sweetener and other components of the gum.
U.S. Pat. No. 4,386,106 discloses a delayed release encapsulated flavorant composition useful in chewing gums. This encapsulated composition is prepared by forming an emulsion of a flavoring agent in a partially hydrophilic matrix material comprising gelatin, a natural gum and plasticizer, drying the emulsion, grinding it, and then coating the resultant powder with a water-insoluble material. Here again, a coating is required so as to form a physical barrier to release of the flavoring component.
U.S. Pat. No. 5,153,011 discloses a flavor ingredient useful in chewing gum compositions, comprising flavoring agent, styrene butadiene rubber, starch or modified starch, optional water and thickeners such as silicon dioxide. The flavoring agent is mixed with the elastomer, whereupon an aqueous starch solution and thickener are added. There is no disclosure or recognition herein that using a cross-linked polymer can provide the additional benefits which the present applicants have discovered.
U.S. Pat. No. 4,992,280 discloses a flavorant release composition comprising polyvinyl acetate having a number average molecular weight of about 150,000 to 200,000 daltons, which composition can be incorporated into chewing gum. It is necessary to dissolve the polyvinyl acetate in a volatile non-reactive solvent as part of the procedure by which the flavorant is incorporated into the product. This patent also fails to disclose or recognize any advantages to the use of cross-linked polymer in preparing a flavorant useful in chewing gums.
U.S. Pat. No. 4,963,369 discloses chewing gums containing porous polymeric beads impregnated with flavor ingredients. The porous polymeric beads can be formed of polymerized styrene cross-linked with divinyl benzene. Such products have a number of characteristics, many of them relatively disadvantageous, by which they can be distinguished from the gums of the present invention. The disclosed polymeric beads must, of necessity, be confined to a particle size below the threshold particle size which may be detected by the consumer upon chewing the gum containing the particles. Otherwise, since the particles are not themselves chewable, their presence would be detected as a gritty or sandy texture which is decidedly undesirable in a chewing gum. Keeping the particles at such a very small size, however, leads to the fact that the particles have a very high surface area-to-mass ratio. This very high ratio, and the very microscopic size of the particles themselves, mean that the flavorant is relatively freely lost from the particulate beads. Accordingly, this patent teaches that it is commonly preferred to apply a coating or other barrier to the beads, after the flavoring agent has been applied into the beads, in order to retard and control loss of flavoring agent from the beads upon mastication of the chewing gum. By contrast, the gums of the present invention comprising discrete macroscopic pieces of cross-linked elastomeric polymer containing flavoring agent contribute to the positive flavor and chewability sensations of the gum even as they are considerably larger than microparticulate size. Moreover, the elastomeric pieces do not require any sort of film or other barrier to the removal of flavor from the polymeric matrix during chewing.
Those familiar with the manufacture of chewing gums and confections are aware that flavoring agents can be vulnerable to gradual degradation in finished products. This degradation can even be accelerated through mediation by one or more other ingredients present in the product. By "mediation" is meant that the presence of such other ingredient(s) in the form in which it or they are present appears to accelerate the decomposition of the flavorant, regardless of whether the mechanism of decomposition is chemical reaction, catalysis of reaction with other components, oxidation, or otherwise. The products which have the potential for mediating the degradation of the flavorants include sweeteners or other agents whose presence is obviously desirable in the final product. Past attempts to prevent or retard degradation of the flavorants have generally involved physically separating or isolating the flavorants within the formulation, by means such as encapsulation or other physical entrapment mechanisms, in order to enable the flavorants present to contribute as fully as desired to the flavor of the final product.
It is also recognized in this art that the consumer's perception of the flavorant(s) upon chewing is important to the acceptance of the gum or confection by the consumer. Attributes including the initial impact of flavor upon the onset of chewing, and the extension of duration of the flavor during chewing, are particularly important, the latter even more so than the former. Achieving a desirable balance of both properties is a challenge, particularly since it is frequently found that techniques which enhance one such property do so to the detriment of the other.
Thus, there is a need for chewing gum and confection compositions which satisfy the objectives of exhibiting a sufficient degree of flavor extension and initial flavor impact while protecting, and even enhancing, the stability of the flavorants present.